Abstract. Gram–positive and gram–negative bacteria are the most common/prevalent human infectious agents. With increased bacterial resistance to the chemical agents, finding herbal combinations with no side effects seems necessary. The aim of this study was to investigate the effect of aqueous, ethanolic and acetonic Quince leaf extracts on the following bacteria: Staphylococcus aureus, Pseudomonas aeruginosa, Escherichia coli, Salmonella typhimurium, Enterobacter aerogenes and Klebsiella pneumonia. Leaves were collected and dried and aqueous, ethanolic, and acetonic extracts were prepared using percolation method. Antibacterial effect of the extracts was determined using agar–well diffusion test and the average diameter of the inhibition zone was measured. Then, using broth macro–dilution test, bacterial minimum inhibitory concentration and minimum bactericidal concentration were determined as well. The results showed that ethanolic Quince leaf extract had the greatest effect on gram–negative and gram–positive bacteria. The aqueous extract showed the weakest effect on tested bacteria. Aqueous, ethanolic and acetonic Quince leaf extracts not only had the inhibitory effect on the bacteria, but also had antibacterial properties. According to the results, Quince leaf extracts can be used against the bacterial infections of the study.